Upon Closer Inspection

Soft, slow-moving, and flightless, caterpillars are among the more vulnerable creatures in nature. Yet caterpillars are not without their defenses. In fact, some caterpillars -- the Anise Swallowtail, for example -- have a number of ways to protect themselves.

The Anise Swallowtail, which matures into a handsome black-and-yellow butterfly with blue accents on its wings, starts life as a little black blob marked with a pale splotch. In other words, the young Anise Swallowtail looks a lot like a bird dropping, a fact that discourages predators from concerning themselves with it.

As the caterpillar grows, eating and molting, its humble disguise gives way to a gaudier outfit of bright green stripes. But by this time the caterpillar has consumed enough of the toxin from the anise plants that it dines on to render itself distasteful to birds, lizards, and whatever else might want to make a meal of it. In addition, the caterpillar now possesses a pair of small orange horns that it can flourish if disturbed. The sudden appearance of these colorful objects, which are otherwise hidden in the caterpillar's head, and the strong odor emitted from them turn away all but the most persistent foes.